Archived posting to the Leica Users Group, 1996/11/24
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On 24 Nov 96 at 16:11, Marc James Small wrote:
> At 09:22 PM 11/24/96 +0000, you wrote:
>
> >Shoot. 39mm by 26 tpi is as much a collision of imperial/metric
> >worlds as using 255/75R16 for tire size.
> >It hurts my eyes. Awful!....:-))
>
>
> But that is EXACTLY the point. It is NOT 39x1mm, it is 39mm by 26tpi.
> Canon made this mistake, too, and that's why they never quite got it right.
> See Dechert's CANON RF CAMERAS for a discussion. Some of the early FED
> cameras show the same mistake.
>
> There was a US ad campaign back in the '60's about a 'silly millimeter' but
> that's really the case here.
>
> It IS 39mm wide by 26 turns per inch. Why Barnack mixed Imperial and
> metric, ich weisse ist nicht. But he did.
Shoot^2....:-))
Aside from the nomenclatura: how on earth can 1mm pitch cause
problems where 26tpi doesn't?
26tpi equals 0.977mm pitch (25.4/26), so there is only 0.023mm
difference pro rotation between the systems. Even with a thread
thickness of 1cm, there wouldn't be problems with binding or
whatever. Heck, with a little stubbornness, one can even jam an M42
male mount all the way down in a T2 female mount (0.25mm difference
pro rotation).
Truely flabbergasted!....8-))
- --
Bye,
_/ _/ _/_/_/_/_/ _/_/_/_/_/
_/ _/ _/ _/ _/ _/ _/
_/ _/ illem _/ _/ an _/ _/ _/ arkerink
_/_/_/
The desire to understand
is sometimes far less intelligent than
the inability to understand
<w.j.markerink@a1.nl>
[note: 'a-one' & 'en-el'!]